Recorder



M. ALDEN Dec. 16, 1952 RECORDER 6 Sheets-Sheet 1 Filed March 11 1950Dec. 16, 1952 DE 2,621,999

RECORDER Filed March 11. 1950 s Sheets-Shet 5 [rzv6 Dec. 16, 1952 M.ALDEN RECORDER Filed March 11. 1950 '6 Sheets-Sheet 4 4 W um: 1 MM w.

71% I I g L M. ALDEN RECORDER Dec. 16, 1952 Filed March 11 1950 s SheetsSheet 5 M. ALDEN Dec. 16, 1952 RECORDER 6 Sheets-Sheet 6 Filed March 111950 ggy 2f! p r QM 7 a MW, a V 4 W/ WM W WM am. ww y 0,. t mm w fl/ 4WM Patented Dec. 16, 1952 UNITED STATES PATENT OFFICE RECORDER MiltonAlden, Wellesley, Mass.

Application March 11, 1950, Serial No. 149,182

12 Claims. 1

This invention relates to recorders and more particularly to recordersof the type wherein a sheet or web of electro-sensitive paper is fedbetween two recording elements or electrodes which are moved relativelyto each other to trace successive lines transversely of the direction inwhich the paper is fed.

There are several ways in which the electrodes can be arranged to obtainsuch a trace, one common way being to position an elongated electrodewith its straight effective recording edge transversely of the paper weband reciprocally to move the effective point of a stylus electrode inthe same plane as that of the effective recording edge of the stationaryelectrode. Alternatively the stylus electrode is rotated in a planenormal to the direction of feed of the paper web, the associatedstationary electrode having a concave effective recording edge whoseradius of curvature has a center point coinciding with that of the axisabout which the stylus electrode rotates. In a third type of recorderone electrode is in the form of a blade or bar having a straightefiective recording edge disposed transversely to the direction in whichthe paper is fed. The other electrode has a recording edge arranged as ahelix whose axis is parallel to the paper web as it is fed between theelectrodes and in a plane passing through the effective recording edgeof the stationary electrode. Relative movement between the electrodes iseifected by rotating the helical electrode about its own axis.

With the advent of high speed recording papers, the operating speed ofrecorders similar to those mentioned above has been limited among otherthings by the eroding of the electrodes due to arcing, ion depositionand mechanical wear and resulting scuffing and abrasion of the recordingpaper and loss of definition in the record. To overcome suchdifficulties, it has been the usual practice to apply the rectifiedincoming signal to the electrodes with such polarity so that theprincipal erosion takes place upon the elongated stationary electrodewhich is comparatively simple and cheap to replace. It has also beenproposed to oscillate the stationary blade longitudinally, such back andforth motion serving to distribute the wear over a greater portion ofthe blade.

Objects of this invention are to provide a recorder which will operateat high speeds, which reduces electrode wear to a minimum, which reducesscuffing and abrasion of the recording paper, which improves thedefinition of the rec-- ord, which permits the positive determining ofthe relationship of the recording electrode with respect to the surfaceof the recording paper, which has means for reconditioning the effectiverecording edge of the electrode, which compensates for irregularities inthe electrodes, which reduces bouncing of the electrodes and whichadvances the recording art generally.

In a broad aspect the invention contemplates moving one electrodetransversely to the direction in which the paper is fed at a rate whichcompensates for wear and erosion. Such electrode movement can be eithercontinuous or intermittent in either direction or reciprocal in oppositedirections as long as the net movement in one direction is greater thanthe movement in the opposed direction so that wear and erosion aredistributed substantially evenly over the entire effective recordingportion thereof.

In another broad aspect the recording element is contacted by stops, thestops limiting the movement of the element under the force exerted bygravity or that of a deformed elastic or yieldable member, for example aspring or rubber snubber, so that the efiective recording edge of theelement bears' a positively determined relationship to the surface ofthe recording paper.

In another aspect the recording element or electrode takes the form of athin strip or ribbon of conducting material which is positioned by stopsor otherwise so that its movement is at all times substantially paralleland its effective recording edge equidistant from a second recordingelement. A portion of the strip is supported by backing means which forexample may be stops, rolls or a slotted backing piece for contactingthe strip so that the effective recording portion thereof conforms tothe configuration of the paper as determined by the other electrode. Toreduce the scuffing and abrasion of the paper to a minimum, theeffective portion of the electrode strip is preferably supported so thatthe plane thereof isat an acute angle to the plane of the paper, theflexibility of strip compensating for any irregularity in the movementof the cooperating electrode;

In one specific aspect the strip or ribbon has its ends joined to form aloop which is carried by two spaced rolls or pulleys so that a portionof the strip is positioned transversely to the direction in which thepaper is fed. Alternatively the strip may be unwound from a reel orspool, the used portion either being wound upon a second spool orperiodically cut ofi and discarded.

In another broad aspect the invention contemplates a recording elementwhich comprises a helically disposed strip of conducting material whichis rotated about the axis of the helix formed thereby by driving means.Resilient means are interposed between the strip and the driving meansto permit displacement therebetween. In a more specific aspect thresilient means comprises an elongated strip of resilient material, suchas rubber which may be either solid or tubular in section, disposedabout the periphcry of a cylinder or drum as the single turn of a helix.Such tube or strip may be cemented or otherwise secured to the drumperiphery, but is preferably inserted in a slot cut or otherwise formedin the periphery of the drum. A conducting element is cemented orotherwise secured to the outer surface of the resilient tube or moldedin the outer wall thereof.

These and other objects and aspects will be apparent from the followingdescription of specific embodiments of the invention which refer toaccompanying drawings wherein Fig. 1 is a plan view of one embodiment ofthe invention with the cover removed;

Fig. 2 is a sectional view on line 2-2 of Fig. 1;

Fig. 3 is a sectional view on line 3-3 of Fig. 1;

Fig. 4 is an enlarged fragmentary view on line 4-4 of Fig. 1;

Fig. 5 is a view similar to Fig. l showing an alternative construction;

Fig. 6 is a fragmentary view of one type of resilient mounting for theconducting helix;

Fig. '7 is a fragmentary view showing the means for securing the end ofthe conducting helix to the resilient member;

Fig. 8 is a plan view of the top electrode assembly;

Fig. 9 is a side elevation view of the assembly shown in Fig. 8;

Fig. 10 is a bottom view of the assembly shown in Figs. 8 and 9;

Fig. 11 is a section on line llll of Fig. 8;

Fig. 12 is a fragmentary isometric view showing the retails of the bladereconditioning device;

Fig. 13 is a plan View of a second embodiment of the invention;

Fig. 14 is a fragmentary sectional view on line l4|4 of Fig. 13;

Fig. 15 is a fragmentary sectional view on line l5l5 of Fig. 13;

Figs. 16 and 1'? are enlarged fragmentary views showing the details ofthe blade feed mechanism of the embodiment illustrated in Figs. 13through 15; and

Figs. 18 and 19 are enlarged fragmentary sectional views on line l8--I8of Fig. 14 showing the dog in its extreme positions.

Referring to Figs. 1 through 3, the first embodiment of the inventionchosen for purposes of illustration comprises a recorder with a flangedhousing or casing l0 preferably cast and, having a cover 12 attachedthereto by means of hinges M. Leveling screws II are provided in thecasing flange for mounting the recorder upon a supporting structure (notshown). The casing It is divided into two compartments by means of avertical wall or baffie 16. In one of these compartments is a roll ofelectrosensitive recording paper P which wound upon a spool or bobbinwhich is preferably supported by means of a shaft [1 (Fig. 1) and pivot[3 similar to those shown in my copending application Serial No.138,673, filed January 14, 1950.

The second compartment houses a recording 4 element designated generallyas 20 (Fig. 2). To this end the top of such compartment is closed by aplate 22 on the top of which is a platen 23 of insulating material overwhich the web of the recording paper P is drawn from the roll as will bedescribed hereinafter. The plate 22 is supported upon four bosses 23located respectively in the four corners of the compartment, the platebeing secured to the top of the bosses by means of cap screws 24.Depending from the bottom surface of the plate 22 in spaced relationshipare two brackets 26 and 28. Interconnection between the brackets and theplate 22 is made by means of cap screws 2-8 which pass through the platethreadingly to engage the respective brackets.

The bracket 26 is provided with a recess wherein is held the outer raceof a ball bearing 32 (Fig. 2). The inner race of the bearing carries oneend of a stub shaft 34, the other end of which engages the aperture inthe hub of a spider 36. Arranged circumjacent the spider 36 is anannular ring 33 of an insulating material such as a suitable plastic,the ring and spider being attached to each other by means of a lap jointsecured by fiat headed screws all so that the ring and spider form onehead for a cylinder 42 which together with the opposite head 44comprises the drum assembly of the recording element 20. The head 434 isof a nonconducting material and is provided with a recessed hub whereinis carried the outer race of a ball bearing 58. The inner race of thebearing 46 engages a hollow stub shaft or finger 48 one end of which isattached to the frame of an electric motor M. The opposite end of thfinger .18 is reduced in diameter so that it engages an aperture in thebracket 23. Relative movement between the finger 48 and the bracket 28is prevented by a set screw 5%) which engages threads at the bottom ofan aperture in the bracket so that the end of the screw is brought intocontact with a flat upon the end of the finger. The rotatable shaft 52of the motor M projects into the aperture in the spider hub 36, relativerotation therebetween being prevented by means of a pin 54. From theabove it will be apparent that the energization of the motor M from apower source (not shown) by leads extending out for example through thehollow finger 43 will result in the rotation of the recording element 2Bin the bearings 32 and 46.

The motor M is also used to operate the paper feed mechanism. To thisend a worm 56 is secured to or cut integrally upon the portion of thestub shaft 34 between the bearing bracket 26 and the spider hub 36 whichworm engages a gear 58 to form a part of a speed reduction unit 60 (Fig.3) described in detail hereinafter. To prevent overheating of the motorM, a fan 62 (Fig. 2) is secured to the spider hub 3-5 by means of thepin 54 which also couples the hub to the shaft 52 of the motor M asdescribed heretofore. Rotation of fan 62, as the motor M operates,circulates air through the apertures 64 in the cylinder heads M therebyto ventilate the interior of the cylinder 42. Additional breatherapertures 66 and. B8 are incorporated respectively in the brackets 26and 23 and in the side walls of the casing Ill.

The conducting portion of the recording element 20 comprises a strip orribbon 10 of conducting material disposed about the outer periphcry ofthe cylinder 42 as a single turn of a helix. Such conducting strip 10may be either rectangular or circular in cross section, and preferablyalthough not necessarily carried upon a resilient tubular member I2 suchas shown in Fig. 4. When a resilient member is used, it is preferablyretained by the shoulders 14 of a slot helically disposed in the outersurface of the cylinder 42. Alternative resilient members 12a and 12bare shown in Figs. 5 and 6 respectively. Each end of the conductingstrip I9 is secured by a clip I5 (Fig. 7) having two oppositely disposedtabs I6 which are bent around the resilient member I2 and a tongue I8bent down and under the end of the member I2 so that the tongue comesinto electrical contact with an annular disc I8 (Fig. 2) of conductingmaterial attached to the outer surface of the head 44 which acts as aslip ring whereby one terminal of an input signal source is connected tothe strip 19 by means of a brush or other sliding member (not shown)which makes electrical contact with the disc.

The brackets 25 and 28 are proportioned with respect to the diameter ofthe cylinder 29 so that the cylinder projects through a transverse slot89 (Fig. 1) in the platen 23 with its surface substantially tangent tothe plane of the upper surface of the plate thus bringing the conductor'79 into contact with the web of recording paper P.

As is best shown in Figs. 8 through 11, a recording element assembly 90is pivotally mounted upon the cover I2 so that the effective recordingportion thereof is in the vertical plane passing through the axis of thedrum assembly. The recording element 99 comprises a thin strip or blade92 of flexible conducting material such as stainless steel, whose endsare joined, for example by means of butt welding, to form a continuousloop. This loop is extended between two spaced rolls or pulleys 94 and95 which are journaled in bearings at the respective ends of asupporting frame 95. As is best shown in Fig. 11, the pulley 94 is anidler being rotatably secured to the end of the frame 95 by means of acapscrew and washer 91. continuously driven by a very low speed motor Mswhich is mounted upon the top of the frame 95 so that the blade 92 ismoved around the pulleys 94 and 99 at a rate to compensate for wear anderosion. As the blade 92 is moved, the portion thereof whose lower edgeforms the effective recording edge slides between a flat elongatedportion 99 (Fig. 11) of the frame 95 and a backing member such as thestrip I99 which is secured to such flat portion by means of screws IN,the strip having an offset portion adjacent the flat portion therebyforming a slot which engages the top portion of the blade. Upwardmovement of the blade 92 is further restrained by flanges I92 upon thepulleys 94 and 99.

An idler roll I94 (Fig. 8) is carried upon the end of an arm I99pivotally mounted as at I9'I between the frame 95 and a strap memberIII! which is secured to the frame by screws H2. The arm I95 ispositioned by means of cam H4 so that the roll I99 contacts the innersurface of the portions of the loop 92 opposite the portion secured bythe backing strip I99, as described above, thus t'ensioning the loop.The cam H4 is carried upon a pin H6 whose ends are journaled in theframe 95 and the strap member H9 respectively. The end of the pin H6journaled in the member H9, which extends beyond such member, is knurledpermitting adjustment of the position of the cam, and therefore of theamount of tension in the loop. The adjusted position of the cam H4 ismaintained by a lock comprising a spring loaded ball H8 (Fig. 9)

The second pulley 96 is 6 which selectively engages recesses in the topof the cam as is shown in Fig. 8. The ball biasing spring is maintainedunder compression by means of a set screw H9 which engages a threadedaperture in the frame 95. v

The recording element 99 is pivotally suspended from the cover I2 bymeans of two apertured tabs or ears I29 located respectively at oppositeends of the frame 95. The above mentioned pivotal connections betweenthe recording element 99 and the cover I2 are located so that when thecover I2 is in the closed position, as is shown in Fig. 3, the lowereffective recording edge of the blade 92 is in contact with the web ofthe recording paper P in a vertical plane through the axis of rotationof the drum assembly. The plane of the effective portion of the blade 92preferably is arranged as is shown in Fig. 3 so that such plane makes anacute angle of approximately 69 degrees with the plane of the paper webthereby reducing scufhng and abrasion of the paper. Such angularmounting has the additional advantage ofpermitting the inherentflexibility of the blade 92 to accommodate any misalignment andunbalance in the drum assembly, an important consideration in high speedoperation.

The recording element 99 is brought into contact under pressure with thepaper web by the force exerted by a bent leaf spring I22, one end ofwhich is secured to the frame by means of screws 24. The opposite end ofthe spring is attached to the cover in a similar manner as is shown inFig. 3.

Fig. 3 also illustrates the path of the web of electrosensitive paper Pthrough the recorder. As the web is unrolled from the bobbin by feedrolls I39 and I92, it passes over an idler roll I34 journaled in twobearing brackets I 35 (Fig. 1), thence under two idler rolls I39journaled in the cover in spaced relationship so that the web is heldagainst the platen 22, thence over the apex of a smoothing bar I49having a substantially triangular cross-section, and thence through thefeed rolls I39 and I32. The top roll I32 isan idler which is journaledin the cover I2. The associated driven roll I39 is journaled in thebrackets 26 and 28 and is provided with a gear I42. Meshing with thegear I42 is a, worm I44 carried upon a shaft I49, the other end of whichcarries the above mentioned gear 58 of the speed reduction unit 99. Theshaft I45 is journaled in bearing brarilets I59 projecting from the sideof the cas- When the cover I2 is closed as is shown in Fig. 3, therelationship of the effective edge of the recording strip 92 isdetermined by two stop assemblies I52 and I54 (Fig. 2) supported nearthe top of the inner surfaces of the brackets 28 and 29. The assemblyI52 comprises an L-shaped bracket, one leg I56 of which is secured tothe side of the bracket 28. A tab I58 projects nor mally from the legI59 parallel to the second leg I69 so that a slot is formedtherebetween. A hardened stop pin I62 engages threaded aligned aperturesin the arm I69 and the tab I 58 so that the upper end thereof can bebrought into contact with the lower effective recording edge of thestrip 92. The pin I92 is lock-ed in adjusted position by means of aknurled circular nut I94 which is located in the slot formed between thetab I58 and the arm I99.

As is shown in Fig.12, the stop assembly I 54 is similar in constructionto the assembly I52 described above; but has projecting from the top ofthe arm I60, in addition to the stop pin I62, blade reconditioning meansincluding a hone I 66 and a wiper 129. The hone I66 consists of a blockof abrasive material having a slot in the top thereof through which theblade 92 is moved by the motor Ms so that burrs and irregularities areremoved thereby. The wiper I comprises a piece of leather Ill or similarmaterial folded and held in a spring clip H2 so that the blade 92 passesbetween the folds.

The above described recorder incorporating electrodes including a movingblade in the form of a loop and a resiliently mounted helical conductorpermits operation at a drum speed of 1800 R. P. M. or more as comparedwith ordinary recorders of this type which have been limited to drumspeeds in the order of 300-360 R. P. M. by the abrasion of the paper andlack of definition in the copy.

It is also possible to move the blade electrode in other Ways. Forexample the recorder shown in Figs. 13 through 15 employs a hitch feedfor the blade whereby the blade is moved in successive steps rather thancontinuously. As is shown in Fig. 13, this recorder is generally similarto the recorder described in detail heretofore, having a casing 200wherein is housed a roll of recording paper P and a drum 292 with ahelical conductor superimposed upon its outer periphery preferably bymeans of a resilient member in a manner similar to that describedheretofore in connection with the cylinder 42. As is shown in Fig. 14,the drum driving motor MI is located outside of the drum 202 and iscoupled thereto by means of a speed reducing unit 264 comprising themeshing gears 266 and 288 which are attached to the shafts of the motorand drum respectively. The drum shaft also carries a worm 2M whichengages a gear 2 l2 secured to one end of a short shaft 2M- journaled ina bracket 216. The bracket 21s is in turn carried by a plate 218 whichis attached to the side of the casing 208. The opposite end of the shaft2H3 carries a second worm 222 engaging a gear 222 upon a shaft 224whereon are mounted two paper feed'rolls 226 (Fig. 13).

The shaft 224 also carries a cam 228 (Fig. 16) which is in contact witha cam follower 23c pivotally connected at its lower end to the side ofthe casing 280 as at 232. The upper end of the follower 230 is incontact with an arm 23s extending normally from a slidable member 236carried in a groove in the top of the side of the casing 200. The member236 is biased by means of a spring 238 (Fig. 13) so that the arm 23 ismaintained in contact with the cam follower 23H.

The movable blade 240 is again made in the form of a loop extendingbetween two roll such as the pulleys 242 and 244 jcurnaled at therespective ends of a frame 246. In this instance both pulleys areidlers, and the tensioning means is eliminated so that the blade 24!]fits rather loosely about the pulleys. The driving motor is alsodispensed with, the power for moving the blade 24!] being obtained fromthe drum motor Ml as will be described below.

Pivotally mounted upon the same shaft as the pulley 244 is an arm 250which in turn has a do 252 pivotally mounted upon its projecting end.One end of the dog 252 engages a slot in the slidable member 235 as isbest shown in Figs. 18 and 19.

The opposite end of the dog 252 has a, raised cammed surface formed bythe side of a finger 253 which protrudes from the end of the dog as isbest shown in Figs. 18 and 19. This cammed surface generally conforms tothe shape of the adjacent portion of the blade 244) so that when theslidable member 238 is retracted by the spring 238 to position the dog252 as is shown in Fig. 18, the cammed surface slides over the surfaceof the blade. As rotation of the cam 228 moves the slidable member 238towards the front of the recorder, the dog pivots about the end of thearm 250 thus wedging the blade 240 between the cammed surface of the dogand the pulley 244. Further forward movement of the slidable member 236pivots the arm 254 about the shaft of the pulley 244 so that the blade252 is moved about the pulleys in a counterclockwise direction as viewedin Fig. 19. Upon the return movement of the slidable member 235 by thespring 238, the cammed surface of the dog 252 releases, any reversemovement of the blade 240 during such release being more than overcomeby the blade movement in the opposite direction so that the net movementadvances the blade in a series of steps.

It will be readily appreciated that the use of the above described hitchfeed is not limited to use with a blade formed into a loop, but isequally applicable to advance an expendable blade strip unwound from areel or spool, thence past the effective recording position and thenceonto a receiving reel. Alternatively to rewinding upon a receiving reelused may be periodically cut off by the operator as it leaves therecorder.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

I claim:

1. A reccr comprising two recording electrodes, one or nich is in theform of a strip of electrically conducting material having its endsjoined to form a loop, means for feeding a sheet of electrosensi .276paper between said electrodes, means for locating a portion of theconducting so that the edge thereof is positioned transversely to thedirection of paper feed, and means for progr y moving the strip at arate to compensa for wear and erosion so that the edge presented to theu' is maintained substantially straight.

2. A recorder comprising two recording electrodes, one of which is inthe form of a strip of electrically conductin material having its endsjoined to form a loop, means for feeding a sheet of electrosensitivepaper between said electrodes, two pulleys carrying the strip, means forlocating one portion of the conducting strip extending between the sothat the edge thereof is positioned transversely to the direction ofpaper feed, and means for driving one of said pulleys progressively tomove the strip at a rate to compensate for wear and erosion so that theedge presented to the paper is maintained substantially straight.

3. A recorder comprising two recording electrodes, one of which is inthe form of a strip of electrically conducting material having its endsjoined to form a loop, means for feeding a sheet of electrosensitivepaper between said electrodes, two pulleys carrying the strip, means forlocating one portion of the conducting strip extending between thepulleys so that the edge thereof is positioned transversely to thedirection of paper feed, and an electric motor coupled to one of saidpulleys progressively to move the strip "at a rate to compensate forwear and erosion so that the edge presented to the paper is maintainedsubstantially straight.

4. A recorder comprising two recording elec trodes, one of which is inthe form of a strip of electrically conducting material having its endsjoined to form a loop, means for feeding a sheet of electrosensitivepaper between said electrodes, two pulleys carrying the strip, means forpositioning one portion of the conducting strip extending between thepulleys so that the edge thereof is positioned transversely to thedirection of paper feed, and driving means for one of said pulleysoperated by sheet feeding means progressively to move the strip at arate to compensate for wear and erosion so that the edge presented tothe :paper is maintained substantially straight.

5. A recorder comprising two recordingelectrodes, one of which is in theform of a strip of electrically conducting material having its endsjoined to form a loop, means for feeding a sheet of electrosensitivepaper between said electrodes, two pulleys carrying the strip, means forlocating one portion of the conducting strip extending between thepulleys so that the edge thereof is positioned transversely to thedirection of paper feed, means for tensioning the strip by bearingagainst the strip and means for progressively moving the strip at a rateto compensate for wear and erosion so that the edge presented to thepaper is maintained substantially straight.

6. A recorder comprising two recording electrodes, one of which is inthe form of a strip of electrically conducting material havingits endsjoined to form a loop, means for feeding a sheet of electrosensitivepaper between said electrodes, two pulleys carrying the strip, means forlocating one portion of the conducting strip extending between thepulleys so that the edge thereof is positioned transversely to thedirection of paper feed, tensioning means including a pivotally mountedarm carrying an idler roller which bears against the strip and a cam forvarying the position of the arm and thereby the tension in the strip,and driving means for one of said pulleys for progressively moving thestrip at a rate to compensate for wear and erosion so that the edgepresented to the paper is maintained substantially straight.

7. A recorder comprising two recording electrodes one of which is in theform of a flexible strip of electrically conductingmaterial, means forfeeding a sheet of electrosensitive paper between said electrodes, andmeans for locating a portion of the strip so that the edge thereof ispositioned transversely to the direction of paper feed, the plane of thestrip portion being at an acute angle to the plane of the sheet of paperwhereby the flexibility of the strip compensates for any irregularity inthe movement of the other electrode and minimizes abrasion of thesurface of the paper.

8. A recorder comprising two recording electrodes, one of which is inthe form of a strip of electrically conducting material, means forfeeding a sheet of electrosensitive paper between said electrodes, meansfor locating a portion of the conducting strip so that the edge thereofis positioned transversely to the direction of paper feed, at least oneroll upon which said strip is movably mounted, and means forprogressively moving the strip substantially in one direction only at arate to compensate for wear and erosion so that the edge presented tothe paper is maintained substantially straight.

9. A recorder according to claim 8 wherein the means for locating thestrip includes a backing member having a slot disposed transversely tothe direction of paper feed for slidably engaging the edge of the stripopposite the effective recording edge.

10. A recorder comprising two recording electrodes, one of which is inthe form of a strip of electrically conducting material, means forfeeding a sheet of electrosensitive paper between said electrodes, meansfor locating a portion of the conducting strip so that the edge thereofis positioned transversely to the direction of paper feed, at least oneroll upon which said strip is movably mounted, and driving means forcontinuously moving the stri in one direction at a rate to compensatefor wear and erosion so that the edge presented to the paper ismaintained substantially straight.

11. A recorder according to claim 10 wherein the driving means includesan electric motor.

12. A recorder comprising two opposed recording electrodes, one of whichis elongate, means for feeding a recording sheet between the twoelectrodes, said elongate electrode being movable lengthwise, means forguiding the elongate electrode in its lengthwise movement so that it isalways in operative relationship to the other electrode, and means formovin the elongate electrode lengthwise so that it progresses in onedirection, whereby new portions of the elongate electrode arecontinually brought into operative relationship with the otherelectrode.

MILTON ALDEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,315,348 OBrien Mar. 80, 19432,380,467 Ressler July 31, 1945 2,415,229 Young Feb. 4, 1947 2,444,484 IWise et a1. July 6, 1948 2,495,271 Long Jan. 24, 1950 2,505,779 Long May2, 1950

